Method for controlling the displacement of a part, displaced by an electromotor, of a closure device in a motor vehicle

ABSTRACT

The displacement of a part e.g. window driven by an electromotor in a vehicle is controlled. A jam is identified by comparing a status value (e.g. current or speed) of the electromotor or the closure device with a characteristic value indicating a jam. The position of e.g. the part is detected. The displacement is controlled based on the identification of a jam and the position of the part. If a jam is indicated, the electromotor is stopped for a short time or is reversed. It is determined whether the position of the part has altered or is altering before and/or after the indicated jam. If so, the closing motion is continued, if not, it is assumed that a jam has occurred and the electromotor is reversed. The stopping or reversing time period is so short to be imperceptible to the naked eye.

FIELD OF INVENTION

The invention relates to a method for controlling the displacementmotion of a part of a closure device that is driven by an electric motorin a motor vehicle.

BACKGROUND INFORMATION

Such methods are known from German Patent Publications DE 40 20 351 C2and DE 197 45 597 A1. For recognizing a jamming incident at least onestatus value of the electric motor and/or of the closure device iscompared with a characteristic value that defines a jamming incident.Status values for this purpose are, for example, the displacement force,the motor current, the r.p.m. or the torque moment of the motor. Onecould also think of detecting the positional change of the closuredevice or the speed thereof. The jamming incident is then defined byrespective characteristic values, for example, a maximum displacementforce, a maximum motor current, a minimum r.p.m. and so forth.

OBJECT OF THE INVENTION

In this context, due to external influences, particularly the closing ofvehicle doors and of other movable body parts, forces may be effectiveon the closure device, which forces oppose the displacement motion.Thus, the status values reach the characteristic values, if the forceshave a corresponding strength, for a jamming incident thereby causing anemergency shut-off. The shut-off is characterized by a reversing, thatis, an instantaneous opposite power supply to the motor which leads toan unmistakable backward motion of the moving part, frequently even intothe completely open position thereof. While this cannot be avoided in anactual jamming incident for the protection of possibly pinched-inpersons or body parts, a consumer could interpret this usually completereversal as a failure function in the case that external influencescaused the reaching of the comparing results which indicate a jammingincident.

Thus, German Patent Publication DE 40 20 351 C2 suggests sensing theacceleration forces acting on the vehicle body by a sensor and to takethese forces into account as a base level. However, a detailedembodiment is not disclosed. If one takes into account the strength anddynamic of the acceleration forces acting on a vehicle body, it remainsquestionable whether and how such taking into account is technicallyrealizable in a suitable manner.

On the other hand, German Patent Publication 197 45 597 A1 suggestscontrolling the displacement force of the motor as a sum of a forcenecessary for the displacement of the part and an adjustable excessforce, whereby the displacement force and/or the excess force arecontrolled in closed loop fashion in response to the forces acting onthe vehicle body. Even if one disregards the unclear determination ofthe force necessary for the displacement of the part and the effort andexpense for an exact closed loop control of the displacement forces ofthe motor, the effort and expense for taking the external forces intoaccount has proven itself to be substantial.

Alternatively, a variation of the displacement and/or excess force iscontrolled in closed loop fashion in response to opening and closingprocedures of movable body parts in that the position of the movablebody parts is ascertained by sensors and a variation. Particularlyopening and closing procedures are recognized. In such a case anincrease of the excess force or even discontinuing the pinching-inprotection is suggested. Thus, however the pinching-in danger is put-upwith. Additionally, this requires that the control device receives asignal from the sensors regarding the position change even prior to theoccurrence of a pinching-in recognition.

Thus, it is an object of the invention to provide an alternative methodfor controlling the displacement motion of closure device, which methodmakes possible, on the one hand, a reliable and early recognition of ajamming incident and which, on the other hand, takes into account in asimple manner external influences by movable vehicle body parts.

SUMMARY OF THE INVENTION

The above object has been achieved by the present method for controllinga displacement motion of a movable part of a closure device in a motorvehicle. According to the invention the present method is characterizedby the following steps:

(a) driving said movable part by an electric motor,

(b) determining at least one characteristic value that is significantfor a jamming incident of said movable part,

(c) sensing at least one status value of at least one of said electricmotor and said closure device wherein said at least one status value isalso significant for said jamming incident,

(d) comparing said at least one status value with said at least onecharacteristic value for providing a jamming recognition signal,

(e) sensing a first position of at least one movable vehicle body member(e.g. door) to provide a first position signal,

(f) processing said jamming recognition signal and said position signalto provide a control signal,

(g) stopping said electric motor in response to said control signal fora predetermined length of stopping time (T_(Stop)), wherein saidpredetermined length of stopping time (T_(Stop)) begins at a beginningtime (t_(x)) when a jamming incident starts,

(h) determining, starting with said first position signal, whether aposition change is taking place or has taken place within apredetermined time range (t_(x)±ΔT) prior to or after the occurrence ofsaid jamming recognition signal to provide a second position signalindicating a position change,

(i) continuing a displacement motion of said movable part in response tosaid second position signal, or

(j) assuming in the absence of said second position signal, the presenceof a jamming incident and reversing said electric motor.

Thus, when a comparing result indicates that a jamming incident exists,the electric motor is stopped for a predetermined, short time duration,or alternatively, it is reversed. Thereby it is examined whether, withina given time range prior to and/or after the occurrence of a comparingresult indicating a jamming incident and starting from a predeterminedfirst position of the vehicle body part, a change of the positionoccurred and/or is occurring.

If within this time range the position signal indicates a changerelative to the first position of a vehicle body part, the displacementmotion in the closing direction is continued, otherwise a jammingincident is assumed to exist and the electric motor is reversed and/orthe reversing is continued.

Thereby, the time duration may be determined corresponding to thereaction time of the sensor and the traveling time of the positionsignal up to the control to be so short that the customer does notnotice this pause or the short time reversing during this time durationor at least it is not noticed as a disturbance. Particularly, timedurations of about 150 to 100 msec or even shorter have been found to besufficient to distinguish, by monitoring the sensors, between an actualjamming incident and an occurrence of comparable force caused by theclosing of a vehicle body part, particularly the door. If one takes intoaccount that the moved part including the mechanical components firsthave a substantial inertia and thus hardly come to an actual stop withina time duration of about 100 msec even if a reversing current is appliedand additionally the time duration is too short with regard to thereceptivity of the human eye, it becomes clear, that the customer willnot notice even a reversing introduced for a short duration. On theother hand, the short duration stopping or the reversing have acritically higher safety in case of an actual jamming incident comparedto the known alternatives of the prior art of a threshold increase oreven a deactivation of the jamming protection.

A first further embodiment of the method is provided when a comparingresult indicating a jamming incident and the first position of thevehicle body part are present simultaneously wherein first the electricmotor is stopped or reversed again for the predetermined time durationand wherein the displacement motion is continued provided that withinthis time duration the position signal indicates a change of a vehiclebody part relative to the first position. Thus, the case is covered inwhich the position signal arrives with such a delay, for example due toa slow data transmission, that the recognition has already responded inthe case of respectively strong shock vibrations.

A second further development of the method is results, if starting fromthe given first position, a change of the position of the vehicle bodypart is recognized and if within a predetermined time range startingwith this change, a comparing result occurs indicating a jammingincident. In this case the electric motor is also stopped for thepredetermined time duration and the displacement motion is thencontinued, whereby the time duration of this stop does not need to beidentical to that of the first further development, preferably it isclearly shorter. This further development thus covers the case whereinan already recognized door closing operation is immediately followed bya jamming incident.

The characteristic values for comparing with the status values which aresignificant for a jamming of a part, are adapted at a first position,particularly at an open position of a vehicle body part in a directionof a timewise later jamming recognition. An adaptation in the directionof a timewise later jamming recognition means for example an increase ofthe jamming characteristic value of the motor current or a reduction ofthe characteristic value of the r.p.m. and/or the displacement speed.Besides that, the characteristic values can be adapted for the comparingwith the status values that are significant for the jamming of a part inresponse to the position and the motion direction of the movable part.

In a preferred manner the jamming recognition thus remains basically inan active state even after the end of the time duration of the stoppingor of the reversing, if indicated, with relatively high characteristicvalues, so that a jamming incident occurring actually simultaneouslywith the closing of a door, is recognized even if the displacement iscontinued and a respective emergency shut-off is initiated.

The invention shall be explained in more detail in the following withreference to an example embodiment and the Figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the sequence of the method and the curve of the motorcurrent and of the jamming current characteristic value when theposition of the door is changed;

FIG. 2 shows the door position sensor signal;

FIG. 3 shows the sequence of the method with a short duration reversing;and

FIG. 4 shows the motion change of the moved part per time unit duringthe method.

DETAILED DESCRIPTION OF PREFERRED EXAMPLE EMBODIMENTS AND OF THE BESTMODE OF THE INVENTION

FIG. 1 shows the curve of the motor current I(t) of the electric motoras a status value that is significant for a jamming. In an analog mannerother status values can also be used, as explained above, for examplethe displacement speed of the closure device. The motor current I(t) iscompared with the jamming current characteristic value, which, in theespecially preferred embodiment of FIG. 1, assumes the values 10, 11, 12or 13, whereby the selection of the value takes place in response tocertain occurrences and will be explained in more detail below.

FIG. 2 shows the position signal of a sensor which senses the positionof a movable vehicle body part, in this case a door. The sensor in thisexample is a door switch with the signal states door open or doorclosed. For faults in the jamming recognition the vibration shock whenclosing the door is thereby especially of interest.

When a comparing result in t_(x) indicating a jamming incident ispresent, the electric motor is stopped for a predetermined time durationT_(Stop) and the motor current I(t) drops. It is checked whether withina predetermined time range t_(x)±ΔT prior to and/or after the occurrenceof the comparing result that indicates the jamming incident, andstarting from a given first position, in this case “door open”, of thevehicle body part, a change in the position (door=>closed) has occurredor is occurring. In this case the displacement motion is continued as isshown at t₄ in FIG. 1. Otherwise, a jamming incident is assumed and theelectric motor is reversed.

The observation of the time range t_(x)±ΔT prior to and/or after theoccurrence of the jamming incident at t_(x), takes into account theconnection of the position sensor to the control system which connectionmay quite differ in the different systems. Thus, when a directconnection, for example of the door switch to the door control devicewhich is responsive for the displacement control of the window panes,the signal, the position change can be actually evaluated even prior tothe recognition of the jamming incident which was caused by vibrationshock and thus is not real. However, if the door switch is interrogatedthrough a central CAN-bus, it is possible, until the arrival of theinformation regarding the position change, that the jamming incidentcaused by vibration shock has already been recognized. Also in this casean erroneous reversing can be avoided by the stop for the predeterminedtime duration T_(Stop) when an immediately preceding closing of the dooris recognized without the need for cancelling the jamming protection.

The length and orientation of the time range (t_(x)±ΔT may, but does notneed to, lie prior to or after the occurrence of the jamming incident att_(x). Particularly, this time range does not need to be symmetricalrelative to the jamming point of time t_(x). By way of this timeinterval the following are taken into account: the delayed propagationof a vibration shock in response to a position change of a vehicle bodypart, which propagation must be individually adapted for each vehicletype, the delay in the response of the jamming recognition, and thetravel time of the position signal.

If one can start with the assumption that the position change alwaystakes place after the response of the jamming recognition, a firstfurther development of the method results. Thereby, the electric motoris Stopped again for the predetermined time duration T_(Stop) if thecomparing result (i(t)=11), that indicates the presence of a jammingincident, and the first position of the vehicle body part (door open) att_(x) are present simultaneously, and the displacement motion iscontinued if within this time duration the position signal indicates achange relative to the first position of a vehicle body part. The timerange to be considered and shown in FIG. 1 as (t_(x)±ΔT) thencorresponds to T_(Stop). In that case a position change is expected onlystarting at t_(x). In a simple example embodiment this means that theposition of the doors of the vehicle is monitored and that the electricmotor is first Stopped for a predetermined time duration if thecomparing result, which indicates a jamming incident, and the positionsignal, which indicates an open door, are present simultaneously. Thenthe displacement motion is continued if within this time duration a doorclosing is indicated.

A second further development of the method is obtained in the reversecase when the position change can always be recognized prior to theresponse of the jamming recognition. If, starting from the predeterminedfirst position (door open) a change in the position of the vehicle bodypart is recognized and if a comparing result indicating a jammingincident occurs within a predetermined time range, starting with thischange, the electric motor is also Stopped in this case for thepredetermined time duration and the displacement motion is thencontinued. Thereby, the time duration of this Stop does not need to beidentical to that of the first further embodiment, preferably it isclearly shorter.

The length of the time duration T_(Stop) is thereby selected to berelatively short and takes into account, above all, the signal traveltime and the decay of the vibration shock. Experiments have shown thatthe time duration for T_(Stop) of about 100 msec and below aresufficient for this purpose. In the most advantageous case the part tobe moved thereby does not at all come to a full Stop. This shortinterruption, in any case, is not noted by the customer or at least itis not noted as being disturbing.

A multitude of possibilities are available for the renewed start-uprequired for continuing the displacement motion, in order to avoid orlimit the danger of jamming also in this instance. The renewed start-upcauses a higher start-up current, however, this higher start-up currentexceeds, between t₄ and t₅, the low thresholds 10 or 11 that arecustomary for the jamming recognition, only for such a short time thatthe pane has not moved at all in this time range or it has made onlysuch insignificant advance that a jamming cannot occur.

Further, the characteristic values for comparing with the status valuesthat are significant for a jamming of the part, can be adapted by takinginto account the position and motion direction of the movable part. Thistakes place, for example, in this example embodiment, in that firstbetween t₀ and t₁ the start-up of the pane in the inner area of thedoor, where there is no danger of jamming, is compared with a highthreshold 13. Starting with t₁ a switch to a clearly lower threshold 11is performed, whereby threshold 11 is somewhat higher than threshold 10.Namely, an open position of a vehicle body part is present, in this caseof the door, so that in this especially preferred embodiment thecharacteristic values for comparing with the status values, that aresignificant for a jamming of the part, are adapted in the directiontoward a timewise later jamming recognition, that is: they are increasedfrom 10 to 11, in order to neutralize smaller vibration shocks alreadyin this manner.

For the renewed start-up at t₄ the characteristic value is temporarilyincreased to the threshold 12, which however can be selected to besmaller than 13. Starting with t₅, preferably even before the actualbeginning of the continuation of the displacement motion of the pane,the characteristic value is also switched to the lowest threshold 10,because the door is now closed.

Especially preferred is the use of the method known from German PatentPublication DE 197 10 388 A1 of the applicant, wherein in each phaseincluding the start-up phase, a jamming can be recognized at any time,so that especially also during a renewed start-up a jamming is certainlyrecognized.

FIG. 3 still illustrates the alternative embodiment wherein, when acomparing result is present indicating a jamming incident, the electricmotor is even reversed for a time duration T_(rev), that is, the motoris energized in the opposite direction. Thus, the motor current in FIG.3 becomes substantially negative. Thereby it is again tested, in ananalog manner, at the door sensor, whether in the predetermined timerange t_(x)±ΔT prior to and/or after the occurrence of the comparingresult indicating the jamming incident and starting from a predeterminedfirst position, in this case “door open”, of the vehicle body part, aposition change has taken place (door=>closed) or is taking place. Inthis case the displacement motion is again continued in the closingdirection as also seen at t₄ in FIG. 3. Otherwise a jamming incident isassumed and reversing of the electric motor is continued.

FIG. 4 thereby additionally sketches the actual motion change of thepart being moved per unit of time during this method, particularlyduring the reversing according to FIG. 3, and it makes clear that theactual reverse motion of the part being moved also during reversing isso small and of such short duration due to the inertia of the mechanicalsystem that the customer will not be able to notice this with the nakedeye. This is a fact for time durations of 100 msec solely due to thelimits of perception. If one additionally takes into account the ratioof the time duration T_(rev) of the reverse energizing to the timeduration T_(ruc) of the actually backwards directed motion of the movedpart, it becomes clear, that time durations clearly above 100 msec wouldstill be sufficient to assure that the reverse motion is not perceptiblefor the customer's naked eye. The limits will differ from one system tothe other. One can start from the assumption that even a reverseenergizing or a Stopping in the range of one second is hardly noticeableon the actual motion change of the pane.

A further alternative not shown in the Figures results form thecombination of the two alternatives of reversing and stopping in atimely sequence, that is, one first energizes reversed for a shortduration, for example in order to actually and quickly bring the movedpart to a Stop, to which subsequently is added a Stop phase, that is aphase without an energizing current, provided a position change of thevehicle body part has not yet been recognized at that time. An actuallyopposite sequence is also possible.

Although the invention has been described with reference to specificexample embodiments, it will be appreciated that it is intended to coverall modifications and equivalents within the scope of the appendedclaims. It should also be understood that the present disclosureincludes all possible combinations of any individual features recited inany of the appended claims.

What is claimed is:
 1. A method for controlling a displacement motion ofa movable part of a closure device in a motor vehicle, said methodcomprising the following steps: (a) driving said movable part by anelectric motor, (b) determining at least one characteristic value thatis significant for a jamming incident of said movable part, (c) sensingat least one status value of at least one of said electric motor andsaid closure device wherein said at least one status value is alsosignificant for said jamming incident, (d) comparing said at least onestatus value with said at least one characteristic value for providing ajamming recognition signal, (e) sensing a first position of at least onemovable vehicle body member (e.g. door) to provide a first positionsignal, (f) processing said jamming recognition signal and said positionsignal to provide a control signal, (g) stopping said electric motor inresponse to said control signal for a predetermined length of stoppingtime (T_(Stop)), wherein said predetermined length of stopping time(T_(Stop)) begins at a beginning time (t_(x)) when a jamming incidentstarts, (h) determining, starting with said first position signal,whether a position change is taking place or has taken place within apredetermined time range (t_(x)±ΔT) prior to or after the occurrence ofsaid jamming recognition signal to provide a second position signalindicating a position change, (i) continuing a displacement motion ofsaid movable part in response to said second position signal, or (j)assuming in the absence of said second position signal, the presence ofa jamming incident and reversing said electric motor.
 2. The method ofclaim 1, further comprising the steps of (a) checking whether said firstposition signal indicates at t_(x) said vehicle body member in an openposition (door open at t_(x)) and whether said jamming recognitionsignal and said first position signal are present simultaneously, if so:(b) the electric motor is first stopped for the predetermined length ofstopping time (T_(Stop)), or it is reversed, then (c) checking whetherwithin this predetermined length of stopping time (T_(Stop)) said secondposition signal occurs, if so: (d) continuing the displacement motion ofsaid movable part in the closing direction, and if not (e) assuming ajamming incident and reversing the electric motor.
 3. The method ofclaim 2, wherein said vehicle body member is at least one door, saidmethod further comprising the steps of: (a) monitoring whether said atleast one door is open to produce said first position signal as a “dooropen” signal, (b) checking whether said jamming recognition signal andsaid “door open” signal are present simultaneously, and if so (c) firststopping said electric motor for said predetermined length of stoppingtime (T_(Stop)), (d) checking whether within said predetermined lengthof stopping time (T_(Stop)) a door closing takes place, and if so (e)continuing said displacement motion.
 4. The method of claim 1, furthercomprising the steps of: (a) checking whether and when said secondposition signal occurs, (b) checking whether, within a predeterminedtime interval starting with the occurrence of said second positionsignal, said jamming recognition signal occurs; (c) stopping saidelectric motor for said predetermined length of stopping time (T_(Stop))and then resuming said displacement motion.
 5. The method of claim 1,further comprising the steps of (a) determining a plurality ofcharacteristic values significant for a jamming incident, (b) checkingwhether said at least one vehicle body member is open, and if so (c)adapting said plurality of characteristic values relative to a timewiselater jamming recognition signal so that an adapted characteristic valueis larger than a preceding characteristic value (11>10).
 6. The methodof claim 1, further comprising (a) determining a plurality ofcharacteristic values significant for a jamming incident, (b) sensing acurrent position of said movable part of said closure device to providea current third position signal, (c) sensing a motion direction of saidmovable part of said closure device to provide a motion directionsignal, and (d) adapting said characteristic values in their size inresponse to said current third position signal and in response to saidmotion direction signal.
 7. The method of claim 1, further comprisingdetermining said predetermined length of stopping time (T_(Stop)) soshort that a motion of said movable part, as it is being moved in amotion direction opposite to a preceding motion direction, cannot beperceived by a naked eye.
 8. The method of claim 7, comprisingdetermining said predetermined length of stopping time T(_(Stop)) to beless than 150 msec.
 9. The method of claim 8, comprising determiningsaid predetermined length of stopping time (T_(Stop)) to be less than100 msec.
 10. The method of claim 1, further comprising (a) firstreversing said electric motor in response to the presence of saidjamming recognition signal for a predetermined length of reversing time(T_(rev)), and then (b) stopping said electric motor for saidpredetermined length of stopping time (T_(Stop)).
 11. The method ofclaim 1, further comprising (a) first stopping said electric motor inresponse to the presence of said jamming recognition signal for saidpredetermined length of stopping time (T_(Stop)), and then (b) reversingsaid electrical motor for a predetermined length of reversing time(T_(rev)).